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| author | Gautham R. Shenoy <gautham.shenoy@amd.com> | 2025-11-07 10:41:43 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-11-24 12:35:53 +0300 |
| commit | 49a1b7d2f0ca17dca1ccc89aa96fbbb5ca3bf292 (patch) | |
| tree | 1e10cdc7e705cbe7a7cb22187e1c530314278180 | |
| parent | 944b13dade4ba835d76ee59bf7ccbbf4df3ede5f (diff) | |
| download | linux-49a1b7d2f0ca17dca1ccc89aa96fbbb5ca3bf292.tar.xz | |
ACPI: CPPC: Perform fast check switch only for online CPUs
[ Upstream commit 8821c8e80a65bc4eb73daf63b34aac6b8ad69461 ]
per_cpu(cpc_desc_ptr, cpu) object is initialized for only the online
CPUs via acpi_soft_cpu_online() --> __acpi_processor_start() -->
acpi_cppc_processor_probe().
However the function cppc_allow_fast_switch() checks for the validity
of the _CPC object for all the present CPUs. This breaks when the
kernel is booted with "nosmt=force".
Check fast_switch capability only on online CPUs
Fixes: 15eece6c5b05 ("ACPI: CPPC: Fix NULL pointer dereference when nosmp is used")
Reviewed-by: "Mario Limonciello (AMD) (kernel.org)" <superm1@kernel.org>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://patch.msgid.link/20251107074145.2340-4-gautham.shenoy@amd.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/acpi/cppc_acpi.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 3ce5bb87d25b..c4a1fee4b487 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -463,7 +463,7 @@ bool cppc_allow_fast_switch(void) struct cpc_desc *cpc_ptr; int cpu; - for_each_present_cpu(cpu) { + for_each_online_cpu(cpu) { cpc_ptr = per_cpu(cpc_desc_ptr, cpu); desired_reg = &cpc_ptr->cpc_regs[DESIRED_PERF]; if (!CPC_IN_SYSTEM_MEMORY(desired_reg) && |